Classifier



H. s. COE

cLAssIF'IER June 21, 1927.

Filed Nov. l2. 1923 2 Sheets-Sheet l INVENTOR BY W19 Wa/Lam H15 ATTORNEY H. S. COE

CLAS S IFI ER June 21, 1927.

Filed Nov. 12. 1923 2 Sheets-Sheet 2 /1/ t S' INVENTOR BY- @M4-w W v ma ATTORNEYS qll Patented June 21, 1927.

UNITED STATES HARRISON BTBEETEB COE, 0F LWRENCE, KANSAS.

CLASSIFIED.

Application led November 12, 1923. Serial N o. 674,105.

The present invention relates toA wet classifiers and has for its object the provision of an improved wet classifier. Certain lfeatures herein described and claimed were disclosed in my prior application Serial No. 434.576, filed January 3, 1921, copending with and abandoned in favor of this application.

The improved wet classifier of the invention belongsto that general type in which advantage is taken of the differential rate of settling of fine or light solid particles and coarse or heavy solid particles in a liquid (such as water) for the purpose of effecting a separation of the fine and coarse particles into two classes or products. In apparatus of this type the solid particles .in the form of a pulp, that is, mixed with an appropriate liquid, are subjected to set-- fling by gravity in the course of which the coarse or heavy particles settle more rapidly than do the fine or light particles. In consequence of this differential rate of settling between the coarse or heavy particles r and the fine or light particles, the fine or light particles remain in large part suspended in the supernatant liquor, while the coarse or heavy particles in large part settle towards and on the bottom of the apparatus. Vet classifiers of this type are used extensively in ore dressing operations as well as in many metallurgical and chemi cal operations. In the dressing and metallurgical treatment of ores, the ore is first crushed and ground to relatively small particles, usually in the presence of an appropriate liquid such, for example, as water. The resulting mixture of finely ground ore particles and liquid constitutes the ore pulp and is fed to the classifier wherein is effected the desired separation of the coarse or heavy particles from the fine orl light particles. The coarse or heavy particles are frequently described as the sands, while the light or fine particles are frequently called slimes.

The improved apparatus of the invention comprises a vessel having an inclined bottom surface of which a substantial area is above the normal operating liquid level in the vessel and constitutes a draining area. A solids discharge outlet is associated with this draining area and a conveying element is operatively mounted in proximity to the bottom surface of the vessel and is provided with a plurality of scoop-like members adapted to move through the liqannular path across the draining area to the solids discharge, while at the same time permitting the drainage of liquid from the solid material as it isv carried along the path. In the course of the movement of the conveying element, the scoop-like members pass below the normal liquid level in the vessel and engage material collecting at the outer part of the bottom and below the liquid surface and drag such material over the bottom surface out of the liquid zone and over the draining area or drainage zone above the liquid level. The conveying element ordinarily carries scrapers or plows working in conjunction with the scoop-like members and adapted to prevent such solid material as may escape from the scoop-like members from lodging on the inner area of the draining zone or area whereby the inner area of the draining zone is kept clear and unobstructed for the free passage of the draining liquid back to the body of the pulp in the vessel.

The construction and mode of operation of what I now regard as the preferred embodiment of the improved wet classifier of the invention will be understood Ifrom the following description taken in connection with the accompanying drawings, in which:

Fig. l is a plan of the apparatus; Fig. 2 is an elevation of the apparatus, and Fig. 3 is a sectional elevation taken on the section line 3 3 of Fig. 2.

In the apparatus illustrated in the accomi panying drawings, the settling vessel or basin 5 is square in section. I prefer to construct the settling vessel or basin of square section in classifiers up to about 2O feet in width, while in larger apparatus I prefer to construct the settling vessel or basin of circular section. 1-

The settling basin has an inclined bottom 6, preferably pitched at an angle of about 20 with the horizontal. The upper edge or rim of the settling vessel is substantially in a horizontal plane so that the vessel has a relatively deep lower e'nd and a relatively shallow upper end.

A feed box 7 is associated with one side of the relatively deep lower end of the settling vessel. The pulp to be treated in the classifier-flows into the feed-box 7 from a feed- )ipe 8 and over an adjustable Weir 9 into t 1c settling basin. The overflow of the classifier' is taken off at the opposite corner of the deep lower end of the settling vessel. To this end an L-shaped overflow discharge box 10 is associated with the opposite corner of thc settling vessel. The slimes flow from the settling basin over the adjustable weirs 11 into the box 10 and thence to the slimes discharge outlet 12.

The conveying element of the classifier is carried by an inclined shaft 13., This shaft is operatively carried by a super-structure comprising an overhead beam 14 and two uprights 15. The shaft 13 is centrally disposed with respect to the inclined bottom 6 of the settling vessel and is mounted erpendieular to the plane of the inclined ottom 6. The shaft 13 is suspended in appropriate bearings carried by the super-structure and is adapted to be driven by a gear wheel 16 and cooperating worm 17 ;I the worm being driven by a pulley 18 and cooperating belt 19 from any suitable power source.

A circular spider 20 is secured to the shaft 13 at its lower end and in proximity to the inclined bottom 6. The external periphery 21 of the spider 20 is several inches in width or depth, but its bottom 21 is a substantial distance above the bottom 6 of the settling vessel to allow the solids (sands) to pass freely thereunder. A circular ring 22, somewhat wider or deeper than the peripheral rim 21, is arranged concentric with and spaced from the rim 21.

A plurality of spaced scoops 23 are arranged betWeen the rim 21 and the ring 22 vand are bolted to the rim and ring to form a substantially unitary structure. The scoops 23 are of substantially the same height or depth as the ring 22. The scoops 23 are so arranged that their concave surfaces are in front during the normal operating rotation of the conveying element, indicated by the arrow in Fig. 1, so as to gather up and carry the solids (sands) in a manner to be later described. It should be understood that the scoops 23 may be mounted about the shaft 13 in any appropriate manner. The presence of the rim 21 and ring 22 is not essential to the operation of the scoops, but this construction together with the spider 20 gives unusual strength and rigidity. It is sometimes advantageous to modify the shape of the scoops 23. They may, for example, be made V-shaped instead of in the shape indicated in Fig. 1.

Each of the four spokes of the spider 2O carries a rake or scraper 24. The rakes 24 are mounted at progressively varying distances from the shaft 13 with the object of Working over substantially the entire area of the inclined bottom 6 directly beneath the spider 20. The lower edges of the rakes move in proximity to the inclined bottom 6.

accumulated solid material so as to permit it to flow into the path of the scoops. Above the liquid level they may operate to work the solid material escaping or slopping over from the sides of the scoo s in tnree different ways depending upon tie angle at which they are set. Accordmgly the rakes may be set so as to work the solid material on the draining area away from the center of the draining area, or to push the solid material ahead of them over the surface of this area, as illustrated in the drawings, or to work the solids inwardly toward the center of the apparatus. Furthermore, these rakes may act merely to stir up the solid material on the draining area, this continuous stirring serving to keep the solids in such condition that they are readily Washed back into the pulp by even a relatively smallA amount of liq'llrld,

he normal operating liquid level in the settling basin 6 will, of course, be determined by the height of the adjustable weirs 9 and 11. In Figs. 2 and 3 of the accornpanying drawings, dotted lines A indicate approximately the normal operating liquid level in the set-tling basin. A solids (sands) discharge outlet.25 is provided on the draining area section of the inclined bottom 6. The discharge outlet 25 is positioned in the path of the scoops 23 and just preceding or in advance of the point where these scoops return into the liquid in the settling vessel, after having passed over the draining area of the inclined bottom 6.

The operation of the apparatus is as follows.. The pulp to be subjected to the classifying treatment flows into the feed box 7 and over the weir 9 into the settling vessel or basin 5. The level of the pulp in the settling basin is approximately indicated by the dotted lines A of Figs. 2 and 3. The solid particles in the pulp undergo differential settling in the basin 5, the line or light particles remaining in large part in suspension in the liquid while the coarse or heavy particles settle towards and on the bottom of the vessel. The line or light particles in sus ension are carried away-with the overflow rom the settling vessel into the'box 10 and out the slimes discharge outlet 12. The conveying element is rotated at a speed of approximately three revolutions per minute, in the case of a classifier of relatively small size. The scoops 23 move through the pulp in the settling vessel and in the course of this movement pick up and carry out of the pulp a load of the solids (sands). From the time the scoops emerge from the pulp, the load of solids is carried by them without substantial loss and is permitted to drain until the scoops reach the discharve outlet 25, whe-re the solids are dropped through this discharge outlet into a suitable collecting receptacle.

It will be observed that the inclined bottom 6 of the settling basin is divided into two operative portions or sections, as .already indicated, namel f', a lower section containing the pulp an in which differential Settling takes place as hereinbefore described, and an upper or draining section in which the solids removed from the pulp by the rotating scoops are permitted to drain. The rakes 24 in passing over the upper or draining area of the inclined bottom 6 keep this area subst-antiall free of solid matter escaping from the si es of the scoops and thereby permit the free and ready flow of the liquor daining from the scoops 23 across the draining area back into the pulp. 4

Below the liquid level the rakes 24 have two functions. First, to gently stir the settled sands so that any entraincd slimes may escape, and second, to convey the settled solids into the path of the annular system of conveying` scoops or buckets, which ordinarily is accomplished by agitating or stirring the settled solids sufliciently to permit them to flow into this path. But while the rakes may be set so as to Work the settled solids toward the periphery of the lower or settling section of the vessel, they may, under certain circumstances, also be reversed so as to tend to work the settled solids upwardly while passing through the pulp.

Outside the liquid or pulp in the settling vessel, the function of the rakes 24 is to keep the draining area of the inclined bottom G'substantially free of solid material. In general, the angle of the rakes is such that out of the pulp and over the draining area they do not work the solid particles towards the periphery and into the path of the annular system of scoops, but either push the solid particles along substantially in front of them and back to the pulp, rake the particles downwardly, or merely stir them as already described in some detail.

The speed of rotation of the conveying element will be determined by the character of the classification desired. The faster the speed of rotation, the coarser the average size of solid particles in the overflow product and conversely the slower the speed of rotation, the finer the average size of the solid particles in the overflow. As a result of the arrangement of the scoops or buckets 23, the improved classifier ot the invention has a relatively large capacity as compared with other classifiers of the same general dimensions. The apparatus is susceptible of a relatively wide range. in settling capacity, since the adjustable overflow makes possible a iclatively wide variation in' the settling area of the basin. By appropriate adjustment of the speed of rotation of the conveying clement and of the height of the overfiow discharge, relatively wide variations in the classifying operation of the apparatus maybe effected.

The improved apparatus of the invention differs essentially from all other rotary classifiers with which I am familiar in that it collects the coarse material in rotary scoops which rotate around the inner periphery of the settling vessel through the liquid therein and thence over a draining zone and collect the accumulated material as they pass through the liquid from the outer part of the settling area and convey such material with one movement and a single handling over the outer periphery of a drainage zone that in its inner portion is kept free of solids that would divert drainage into the path of succeeding draining material.

In the improved apparatus of the invention, the scoop-like members 23pick up the solid material as fast as it reaches the bottom of the settling vessel 5, and convey that material in a relatively narrow annular path to the solids (sands) discharge outlet 25. The scoop-like members are of such capacity that they engage and carry out of the pulp all of the solid material settling into the path of the scoops through the pulp, and thereby the apparatus is given relatively high capacity with relatively low power required to operate it and wear of parts. i

The portion of the inclined bottom 6 of the settling vessel 5 above the normal operating liquid level may be considered as divided into two sections, namely (l) the annular path over which the solids are moved by the scoop-like members 23 and (2) the draining area or drainage zone below that path. The draining area is kept clear of any solid material leaking out of the scooplike members by the rotating rakes 24, so that the draining area is thus free to receive all of the moisture draining from the solid material carried along by the scooplike members and to convey such moisture directly back to the pulp in the settlingr vessel. The tWo sections of the inclined bottom 6 above the pulp level have distinctly different functions, the outer section servingr as a path over which solid material (sands) is conducted to the discharge, while the inner section serves to conduct the moisture. draining from the material passing over the outer section, directly back to the pulp.

The rotating conveying element of my improved classifier is of very rigid construction. The plane of the bottom of this element is in close proximity to and close alignment with the inclined bottom 6 of the settling vessel. Suflicient mechanical clearance is, of course, provided, between the bottom of the rotating conveying element and the inclined bottom`6 to permit free rotation of the element, to allow opportunity for drainage of moisture from the scoop-like members, and to allow the sands to pass into the path of the scoops in the lower or settling portion of the vessel. The conveying element is preferably suspended from overhead bearings. and may be so mounted as to allow of adjustment of the amount of clearance between it and the bottom of the settling vessel. The power consumption is relatively low in comparison with tlie capacity of the apparatus. In an apparatus eight feet in width, I have secured excellent results by spacing the rim 21 and ring 22 approximately one foot apart, and providing sixteen equally spaced scoop-like members 23. In this machine the ockets or buckets so provided were approximately eight inches in depth or height. Thesedimensions are given merely as illustrative, and are of course susceptible of wide variations without departing from the spirit and scope of the invention. The spider 20 may have any desired number of spokes and any desired number of rakes may be mounted upon the spokes.

I claim 1. An apparatus of the character describe comprising a vessel having an inclined bottom surface of which a substantial area thereof is above the normal operating liquid level in the vessel and constitutes a draining area, said draining area of said inclined bottom surface having a solids discharge associated therewith, and a conveying element operatively mounted in proximity to said bottom surface and provided with a plurality o'f scoop-like members having an inner wall formed to oppose downward flow of the solids during upward travel, forming pockets adapted to move through the pulp in said vessel and gather up and remove therefrom a quantity of solid material and to carry such solid material along an'annular path across said draining areato said solids discharge while permitting the drainage of liquid fI-om such solid material as the same is carried along said path, and said vessel having an overflow outlet for liquid by which the liquid portion of the pulp is discharged from the apparatus.

2. An apparatus of the character described comprising a vessel having an inclined bottom surface of which a substantial area thereof is above the normal operating liquid level in the vessel and constitutes a draining area, said draining area of said inclined bottom surface having a solids discharge associated therewith, and a conveying element operatively mounted in proximity to said bottom surface and provided with a plurality of scoop-like members forming pockets adapted to move through the pulp in said 'mitted to flow freely back into the pulp in said vessel.

"3. An apparatus of the character described comprising a vessel having a substantially fiat inclined bottom surface `of which a substantial area thereof is above the normal operating liquid level in the vessel and constitutes a draining area, said draining area of said inclined bottom surface having a solids discharge associated therewith, and a rotary ,conveying element operatively mounted in proximity to said bottom surface and provided with a plurality of scoop-like members having an inner wall formed to oppose vdownward How of the solids during upward travel, forming pockets adapted to move in a relatively narrow annular path near the periphery of said bottom surface and to gather up and remove a quantity of solid material during its passage through the pulp in said vessel and to carry such solid material without substantial loss thereof across said draining area to said solids discharge while permitting the drainage of liquid from such solid material as the same is carried along said path, and said yvessel having an overiow outlet for liquid by which the liquid portion of the pulp is discharged from the apparatus.

4. An apparatus of the character described comprising a vessel having an inclined bottom surface of which a substantial area thereof is above the normal operating liquid level in the vessel and constitutes a draining area, said draining area of said inclined bottom surface having a solids discharge associated therewith, a conveying element operatively mounted in,proximity to said bottom surface and provided with a plurality of scoop-like members forming ockets adapted to move through the pulp in said vessel and gather up and remove therefrom a quantity of solid material and tocarry such solid material without substantial loss thereof across said draining area to said solids discharge while permitting the drainage of liquid from such solid material as the same is carried along said path, and means cooperating with said conveying element for maintaining said draining area substantially fiee of solid material whereby the liquor draining from the solid material carried along by said scoop-like member is permitted to ow freely back into the pulp in said vessel.

5. An apparatus of the character described comprising a vessel having an'inclined bottom surface of which a substantial area thereof is above the normal operating liquid level in the vessel and constitutes a draining area, said draining area of said inclined bottom surface having a solids discharge associated therewith, and a rotary conveying element operatively mounted in proximity to said bottom surface and provided with a plurality of scoop-like members having an inner wall formed to oppose downward iow of the solids during upward travel, forming pockets adapted to move in an annular path near the periphery of said bottom surface and to gather up and remove during its passage though the pulp in said vessel a quantity of solid material and to carry such solid material without substantial loss thereof along a relatively narrow path across said draining area to said solids discharge while permitting the drainage of liquid from such solid material as the same is carried along said path, said solids discharge being so located that the solids carried along by said scoop travel over substantially the entire length of the scoops path across said draining area before reaching the solids discharge, and said vessel having an overflow outlet for liquid by which the liquid portion of the pulp is discharged from the apparatus.

6. An apparatus of the character described comprising a vessel having an inclined bottom surface of which a substantial area thereof is above the normal operating liquid level in the vessel and constitutes a draining area, said draining area of said inclined bottom surface having a solids discharge associated therewith, and a conveying element operatively mounted in proximity to said bottom surface and provided with a plurality of scoop-like members forming pockets adapted to move through the pulp in said vessel and gather up and remove therefrom a quantity of solid material and to carry such solid material along an annular path across said draining area to said solids discharge while permitting the drainage of liquid from such solid material as the same is carried along said path, said conveying element also being provlded with a plurality of rake members operatively positioned to move over said draining area an maintain said area substantially free of solid material whereby the liquor draining from the solid material carried along by said scoop-like members is permitted to flow freely back into the pulp in said vessel.

7. An apparatus of the character described comprising a vessel having an inclined bottom surface of which a substantial area thereof is above the normal oper- -ating li uid level in the vvessel and con-stitutesa raming area, said draining area of said inclined bottom surface having a solids discharge associated therewith,- a conveying,

area and maintain said area substantially ree of solid material whereby the liquor draining from the solid material carried along by said scoop-like members is permitted to .flow freely back into the pul in said vessel'.

8. A maciii comprising a vessel having an inclined bottom surface and an outlet in the upper part thereof, and a rotary conveying element movingr over said surface and including a scoop orming a pocket arranged to engage material collecting on the surface at the lower end thereof and carry it to said outlet, and rakes adapted to agitate the material so as to permit it to move downwardly into the path of said scoop.

9. A machine of the character described comprising a vessel having an inclined bottom surface and an outlet in the upper part4 thereof, a series of radial arms mountedfor rotation about an axis at right angles to said surface, scoops forming pockets on the arms adapted to engage material collecting on the surface at the lower end thereof and carry it to said outlet, and rakes on the arms adapted to agitate the material so as to permit it to move downwardly into the path of the scoops.

10. An apparatus of the character described comprising a vessel having an inne of the character describe clined surface therein upon which solids'.

d associated therewith, and a conveying element operatively mounted in proximity to said inclined surface and provided with a vplurality of scoo -like members having an inner wall forme to oppose downward flow of the solids during upward travel, forming pockets adapted to move throu h the pulp and gather up and remove there rom a quantitl of solid material and to carry such solid material along an annular path across said draining area to said solids discharge while permitting the drainage of liquid from such solid materal as the same is Carried along said path, and said vessel having an overflow outlet for liquid by which the liquid portionof the pulp is discharged from the apparatus.

l1. An apparatus of the character described comprising a vessel having a substantially flat inclined surface therein upon which solids accumulate in settling out of the pulp in the vessel, a substantial area of said inclined surface being above the normal operating liquid level in the vessel and constituting a draining-area, said draining area of said inclined surface having a solids discharge associated therewith, and a rotary conveying element operatively mounted in proximity to said inclined surface and provided with a plurality of scoop-like members having an inner wall formed to oppose downward flow of the solids during upward travel, forming pockets adapted to move in a relatively narrow annular path over said inclined surface and to gather up and remove a quantity of solid material during its passage through the pulp and to carry such solid material without substantial loss thereof across said draining area to said solids discharge while permitting the drainage of liquid from such solid material as the same is carried along said path, and said vessel having an overflow outlet for liquid by which the liquid portion of the pulp is discharged rom the apparatus.

In testimony whereof I aiiix my signature.

HARRISON STREETER COE. 

